1. Field of the Invention
The present invention relates to a method for lighttightly wrapping a stack of photographic light-sensitive sheets and loading such stack by daylight in a lighttight cabinet, and to a photographic sheet stack lighttightly wrapped in back-folded wrapping sheets.
2. Description of the Prior Art
It is known to avoid the use of a darkroom for loading light-sensitive sheets into a sheet processor such as a cassette-loading apparatus, which automatically reloads radiographic film cassettes with a fresh film after an X-ray exposed film has been removed.
These processors usually comprise a film supply magazine in the form of a drawer or the like that can be opened and into which a lighttightly wrapped stack of film is put in daylight conditions. Next, the drawer is closed and an appropriate mechanism cuts or peels the wrapper of the films so that this can be removed from the film stack manually or automatically. One example of suchlike system is disclosed in U.S. Pat. No. 4,909,389 relating to a film-sheet package for use in the magazine of a reloader for radiographic film cassettes. The film wrapper is in the form of a sleeve having a sealed flap for engagement by a winding mechanism. The end opposite to the sealed flap has an open flap folded inwardly to lighttightly close the package. Opening of the package occurs by winding the sealed flap by means of a winding mechanism, the film stack as such being withheld, so that the sleeve is stripped from the stack of film sheets.
While this system works satisfactorily for sheetlike materials such as radiographic film, it is unsuited for larger and heavier sheets such as aluminium offset printing plates, that are image-wise exposed in a plate setter. The size of these plates can amount to 81.times.111 cm, and the weight of a stack of 30 of such plates can amount to 32 kgs.
Attempts have been made to provide a package form that readily lends itself to daylight loading of such plates in a plate setter. However, these package concepts are expensive and/or are ecologically unacceptable.